Any updated gym rules?`

So I was wondering, since I plan on trying the gyms soon, if there has been any major changes to the gym rules since there are now more moves, natures and pokemon. For example a few times now I have seen people get DQ'ed for using greninja in a gym battle. Thats new to me since I was led to believe only legendaries were prohibited. I don't know if someone has already been answered already on this but since I couldn't find a post anywhere on the forums answering this and when I ask in chat I get ignored I figured I'd ask here.

For gym rules, see here. Otherwise, I do not believe there will be any massive changes to the rules, as in the 5.1.1 update, there has not been a sufficient increase in pokemon to warrant a gym update.

"I believe that if life gives you lemons, you should make lemonade... And try to find somebody whose life has given them vodka, and have a party."
- Ron White